Hair Growth/Blood Pressure Drug Minoxidil May Improve Vascular Elasticity

MedicalResearch.com Interview with:

Dr. Beth Kozel M.D.-Ph.D The Laboratory of Vascular and Matrix Genetics LASKER CLINICAL RESEARCH SCHOLAR NIH

Dr. Kozel

Dr. Beth Kozel M.D. Ph.D
The Laboratory of Vascular and Matrix Genetics
LASKER CLINICAL RESEARCH SCHOLAR
NIH

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Elastin is a protein that allows the blood vessels to stretch and recoil. It is made as a child grows but once the child reaches adolescence, the body stops making elastin. With age, the body slowly begins to lose elastin and blood vessels become less flexible.

In order to study what happens when a vessel has less elastin, we used a mouse that makes half of the normal amount of elastin, the Eln+/- mouse. These mice have higher blood pressure, stiffer blood vessels and decreased blood flow to end organs such as the brain. We then used a blood pressure medication, minoxidil (this same medicine when used in topical form helps hair growth), and treated mice from weaning until 3 months of age. With treatment, Eln+/- blood pressure was lower, the vessels were less stiff and blood flow to the brain increased. That effect remained for weeks after the medication was stopped. Additional studies showed that more elastin was present in the vessel wall after treatment and more than 100 other connective tissue genes were also changed, suggesting vessel remodeling. Minoxidil works by causing cells in the blood vessel to relax, leading to a more open, or dilated artery. When taken chronically, our data suggest that the connective tissue associated with a blood vessel remodels, fixing it in a more open state and allowing better blood flow to the organ on the other side, in this case, the brain.

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USPSTF: Behavioral Counseling of Children and Teens to Prevent Skin Cancer Recommended

MedicalResearch.com Interview with:

John W. Epling, Jr., M.D.

Dr. Epling

John W. Epling, Jr., M.D., M.S.Ed., Task Force Member
Dr. Epling is is a professor of Family and Community Medicine at the Virginia Tech Carilion School of Medicine in Roanoke, VA. He is also the Medical Director of Research for Family and Community Medicine, Medical Director of Employee Health and Wellness for the Carilion Clinic, and maintains an active clinical primary care practice. 

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Skin cancer is the most common type of cancer in the U.S., affecting millions of people every year. The Task Force looked at the latest research to see if clinicians can help people prevent skin cancer by providing counseling about ways to reduce risk, including using sunscreen, wearing protective clothing, and avoiding sunlight during peak hours.

Sunburn damaged skin - wiki image

Sunburn damage – wiki image

Based on our review of the evidence, we found that counseling younger patients with a fair skin type and their parents is effective at encouraging these sun protective behaviors. By helping reduce their patients’ exposure to harmful UV rays, clinicians can decrease their risk for skin cancer. As such, we recommend that clinicians provide counseling to people who are six months to 24 years old and have a fair skin type. For adults over 24 with a fair skin type, clinicians should consider the individual’s risks for skin cancer when deciding whether or not to provide counseling.  Continue reading

What is Dandruff and What Can I Do About It?

MedicalResearch.com Interview with:

Dr. Janet Prystowsky, MD Dr. Prystowsky is a leading board-certified dermatologist in New York City.  In addition to her private practice, Dr. Prystowsky is a senior attending physician at Mount Sinai Roosevelt/St. Luke’s Medical Center.

Dr. Prystowsky

Dr. Janet Prystowsky, MD
Dr. Prystowsky is a leading board-certified dermatologist in
New York City. 

In addition to her private practice, Dr. Prystowsky is a senior attending physician at Mount Sinai Roosevelt/St. Luke’s Medical Center.
http://www.janetprystowskymd.com/

MedicalResearch.com: Would you describe what dandruff looks like on most people? 

Dr. Prystowsky: Normal dandruff looks like tiny white flakes or dust in your hair. These flakes are a buildup of dead skin cells mixed with skin oils.

dandruff wikipedia image

Dandruff
Wikipedia image

MedicalResearch.com: Is dandruff the same as seborrheic dermatitis? How does it differ from psoriasis or eczema? Do scientists understand what causes dandruff? Is it caused by stress, diet or fatigue? 

Dr. Prystowsky: Normal dandruff is caused by the accumulation of dead skin cells and skin oils (sebum) that are a part of normal scalp function. Sebum is produced in hair follicle oil glands, and skin cells slough from the scalp surface just as they do from the rest of your body. It is a part of normal skin cell turnover.

However, you may also get excessive dandruff if you have scalp skin diseases such as psoriasis, eczema, and seborrheic dermatitis.  Skin infections with fungus (tinea capitus), head lice, or Staph. Aureus may also trigger excessive flaking. 

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Zika Birth Defects More Severe When Mothers Infected During First Trimester

MedicalResearch.com Interview with:

This image depicts a posterior view of a patient’s back, captured in a clinical setting, upon presenting with this blotchy rash. After a diagnostic work-up, it was determined that the rash had been caused by the Zika virus. Note: Not all patients with Zika get a rash CDC image

This image depicts a posterior view of a patient’s back, captured in a clinical setting, upon presenting with this blotchy rash. After a diagnostic work-up, it was determined that the rash had been caused by the Zika virus.
Note: Not all patients with Zika get a rash
CDC image

Professor Bruno Hoen, M.D., Ph.D
Dept of Infectious Diseases, Dermatology, and Internal Medicine
University Medical Center of Guadeloupe 

MedicalResearch.com: What is the background for this study?

Response: Zika virus (ZIKV) infection during pregnancy has been identified only recently to cause severe birth defects, including microcephaly, other brain defects, and the congenital Zika syndrome. However, the magnitude of this risk was not clearly defined, with discrepancies between observational data from Brazil and the U.S. Zika Pregnancy Registry. We implemented a cohort study of pregnant women who have been exposed to ZIKV throughout the outbreak that hit the Caribbean in 2016.
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Study Finds Adults Who Used Sunscreen Slightly More Likely To Get Sunburned

MedicalResearch.com Interview with:
“Sunburn” by Beatrice Murch is licensed under CC BY 2.0Dawn Holman, MPH
Behavioral Scientist Division of Cancer Prevention and Control
CDC

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Sunburn at any age increases a person’s chances of developing skin cancer in the future. Using a combination of strategies including staying in the shade, wearing clothing that covers the arms and legs, wearing a hat with a wide brim, and wearing sunscreen (SPF 15+) on exposed skin can protect skin from sun damage and reduce risk of sunburn.

This study used national data to examine how often US adults used these sun protection strategies when outdoors in the sun for an hour or longer and how many US adults got sunburned in 2015.

Among adult women, staying in the shade and using sunscreen were the most common sun protection methods. About 40% of women regularly used these strategies. Women were less likely to wear a wide-brimmed hat (14%) or wear clothing covering their arms (11%) and legs (23%).

Among adult men, wearing pants or other clothing covering their legs and staying in the shade were the most common sun protection methods. Just over 30% of men regularly used these strategies. Men were less likely to use sunscreen (22%), wear a wide-brimmed hat (14%) or wear a shirt with long sleeves (13%).

About one-third of US adults got sunburned in 2015. Sunburn was even more common among certain groups. For example, about half of individuals with sun-sensitive skin and about half of adults aged 18-29 got sunburned.

Certain behaviors and health conditions were related to sunburn. For example, adults who used sunless tanning products to darken their skin, binge drank, engaged in aerobic activity, or were overweight or obese were more likely to get sunburned compared to other adults. Adults who regularly stayed in the shade when outdoors or avoided long periods of time in the sun were slightly less likely to get sunburned compared to other adults.

Adults who regularly used sunscreen were slightly more likely to get sunburned. Continue reading

Dermoscopy Helps Improve Diagnosis of Early Melanoma

MedicalResearch.com Interview with:

Superficial spreading melanoma arising from a dysplastic nevus

Superficial spreading melanoma arising from a dysplastic nevus
NCI image

Aimilios Lallas, PhD
First Department of Dermatology, School of Medicine
Aristotle University
Thessaloniki, Greece

MedicalResearch.com: What is the background for this study? What are the main findings? 

Response: Our goal today is to recognize melanoma at the earliest stage, ideally before it invades the dermis and acquires metastatic potential. Melanoma-specific dermoscopic criteria have been tested mainly in the context of invasive melanoma. Although they were proven valid melanoma predictors, the question still remains if they are strong enough to diagnose melanoma in situ (MIS). Our aim was to investigate the diagnostic accuracy of dermoscopic criteria for the diagnosis of melanoma in situ.

We identified 5 main positive dermoscopic indicators of MIS: atypical network, regression, irregular hyperpigmented areas, prominent skin markings and angulated lines.  Continue reading

Inflammatory Cells That Suppress Skin Allergic Reactions Identified

MedicalResearch.com Interview with:
elstarNidhi Malhotra PhD

Boston Children’s Hospital
Division of Allergy and Immunology
Senior Scientist at Elstar Therapeutics Inc.

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Allergies such as Atopic Dermatitis (AD) are rampant in the industrialized nations. Why are we more predisposed to developing hypersensitive reactions to innocuous proteins (allergens) is not well understood. To gain better understanding and to develop better therapies, we need to first delve deeper into how our immune system regulates homeostasis in tissues such as skin. The main cell types that thwart inflammatory reactions are known as regulatory T cells. These cells are generated in thymus and reside in secondary lymphoid tissues but they are also prominent at tissue sites such as in dermal layer of skin. In this study, I focused on understanding how Tregs resident in skin are distinct from the Tregs in secondary lymphoid organs such as lymph nodes (LNs). I uncovered that functioning of Tregs in skin is underpinned by a distinct set of genes. One main gene that I found to be highly expressed in skin Tregs but not in LN Tregs is Rora, which encodes for the transcription factor ROR alpha (RORa).

This observation was intriguing as previous studies had elucidated the requirement of RORa in the development of inflammatory type-2 innate lymphoid cells (ILC2s) and it has been considered the antagonizing RORa functioning would curb allergic responses. However, I observed that Tregs require RORa to suppress allergic responses. In particular, RORa regulates the expression of a TNF receptor family member DR3, which binds to the cytokine TL1A. TL1A has a role in enhancing suppressive activity of Tregs while also enhancing type-2 cytokine production from ILC2s. Hence, in the absence of DR3 in Tregs, we believe more TL1A is available to ILC2s resulting in unrestrained allergic responses.  Continue reading

Ixekizumab Improved Impact of Genital Psoriasis on Sexual Activity

MedicalResearch.com Interview with:

Dr. Jennifer Cather MD Medical Director at Modern Dermatology and Modern Research Associate Dallas, Texas 

Dr. Cather

Dr. Jennifer Cather MD
Medical Director at Modern Dermatology and Modern Research Associate
Dallas, Texas 

MedicalResearch.com: What is the background for this study? What are the main findings? 

Response: Genital psoriasis can be an uncomfortable and burdensome condition that many people living with moderate-to-severe plaque psoriasis experience. Due to the significant impact, Lilly conducted a 12-week Phase 3b clinical trial with patients with moderate-to-severe genital psoriasis treated with ixekizumab, which found that patients had a greater decrease in the impact of their condition on sexual activity compared to placebo as early as one week.

Specifically, trial patients were randomized to receive ixekizumab (80 mg every two weeks, following a 160-mg starting dose) or placebo and researchers measured pre-specified patient-reported outcomes, including the Genital Psoriasis Sexual Impact Scale (GPSIS), which is composed of the Sexual Activity Avoidance (Avoidance) and Impact of Sexual Activity on Genital Psoriasis Symptoms (Impact) subscales. Patient-reported outcomes were also measured by the Sexual Frequency Questionnaire (SFQ) item 2, evaluating the impact of genital psoriasis on the frequency of sexual activity, and the Dermatology Life Quality Index (DLQI) item 9, evaluating the impact of skin symptoms on sexual difficulties.

At 12 weeks, patients reported the following outcomes:

  • DLQI Item 9 0/1: 92.0 percent of patients treated with ixekizumab compared to 56.8 percent of patients treated with placebo reported no (0) or little (1) sexual difficulties caused by skin symptoms.
  • SFQ Item 2 0/1:  78.4 percent of patients treated with ixekizumab compared to 21.4 percent of patients treated with placebo (reported the frequency of sexual activity was either never (0) or rarely (1) limited by genital psoriasis.
  • GPSIS-Avoidance 1/2:  76.7 percent of patients treated with ixekizumab compared to 25.7 percent of patients treated with placebo reported never (1) or rarely (2) avoiding sexual activity due to genital psoriasis.
  • GPSIS-Impact 1/2:  85.7 percent of patients treated with ixekizumab compared to 52.9 percent of patients treated with placebo reported worsening of genital psoriasis symptoms during or after sexual activity was very low/none at all (1) or low (2). 

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Global Initiative Highlights Inspirational Stories of People Living With Scleroderma

MedicalResearch.com Interview with:

Donald Zoz, MD Senior Associate Director Clinical Development & Medical Affairs IPF/ILD Boehringer Ingelheim Pharmaceuticals, Inc.

Dr. Zoz

Donald Zoz, MD
Senior Associate Director
Clinical Development & Medical Affairs IPF/ILD
Boehringer Ingelheim Pharmaceuticals, Inc.

MedicalResearch.com: What is the background for this platform? Would you briefly explain what is meant by scleroderma? How does it affect a person’s skin and ability to function? Whom does this disease primarily affect? 

Response: “More Than Scleroderma™: The Inside Story” is Boehringer Ingelheim’s new global initiative highlighting real-life, inspirational stories of people living with the rare disease scleroderma. The new effort, created with support from the Scleroderma Foundation in the U.S., aims to raise awareness of the disease, dispel misperceptions and provide important resources to support and guide those on their journey with scleroderma. The initiative’s website http://www.morethanscleroderma.com/us/ features a powerful and inspiring collection of diverse photographs and video profiles of 10 people across the U.S. living with scleroderma and sharing their ‘inside story.’ Each tells their unique and moving experience with scleroderma through diagnosis to learning to live with the disease and manage it.

Scleroderma, also known as systemic sclerosis, is a rare disease characterized by thickening and scarring of the skin, lungs and other organs. Scleroderma affects fewer than 200,000 people in the U.S. and typically affects women in the prime of their lives, between the ages of 25 and 55 taking a marked toll just as they are building their careers and bearing the responsibility of caring for their family. Nearly all people with scleroderma (more than 90%) will develop some skin symptoms including skin thickening, tightened skin around the joints, small red spots on the face and hands and hard lumps on pressure points and joints. Most people with the disease will also develop some degree of lung scarring, or interstitial lung disease (ILD). When the disease’s signature thickening and scarring develops in vital organs, such as the lungs, there are potentially debilitating and life-threatening consequences.  Continue reading

Facial Fillers Carry Rare But Significant Side Effects and Risks

MedicalResearch.com Interview with:

Boris Paskhover, MD Rutgers New Jersey Medical School Adjunct Instructor,Department of Otolaryngology-Head and Neck Surgery NYU Langone Medical Center

Dr. Paskhover

Boris Paskhover, MD
Associate Professor,Department of Otolaryngology-Head and Neck Surgery
Rutgers New Jersey Medical School

MedicalResearch.com: What is the background for this study? What are the main findings?

Response:  Facial fillers include a wide range of cosmetic products used by physicians for augmenting the face. Some fillers are permanent, while others are temporary. Lip filler material is included in this category. Any physician is allowed to perform these procedures but patient’s need to be aware that these are not benign procedures and have some serious complications. It’s important to always go to an experienced facial plastic surgeon, general plastic surgeon or possibly dermatologist for your aesthetic fillers. Our study detailed a decade-long review of FDA reported complications with aesthetic fillers. Continue reading

AI Trained Computer Program Can Monitor Health Forums To Detect Adverse Drug Reactions

MedicalResearch.com Interview with:

Kavita Sarin, M.D., Ph.D.

Dr. Sarin

Kavita Sarin, M.D., Ph.D.
Assistant Professor of Dermatology
Stanford University Medical Center

MedicalResearch.com: What is the background for this study? What are the main findings? 

Response: Drug reactions occur in the majority of patients undergoing cancer therapies. Half of serious drug reactions are detected after market approval which can result in painful complications and interruption in therapy. Post-market drug surveillance platforms such as FDA monitoring rely on medical publications and physician reporting and take time to identify trends. We sought to determine if we could identify trends in patient discussions in internet health forums to more rapidly identify chemotherapeutic drug reactions. We chose skin reactions as a proof-of-principle because patients can more easily describe what they see on their skin.

Julia Ransohoff, a medical student, and Azadeh Nikfarham, an informatics postdoctoral fellow trained a computer to recognize when a patient undergoing anti-cancer treatment with PD-1 antagonists or EGFR-inhibitors described a drug reaction in their internet forum posts.

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Shingles Can Occur At Chickenpox Vaccination Site in Healthy Children

MedicalResearch.com Interview with:

Depicted here, is a close-up of a maculopapular rash that was diagnosed as a crop of chickenpox lesions.

Depicted here, is a close-up of a maculopapular rash that was diagnosed as a crop of chickenpox lesions.
“Dew-drop on a rose petal pattern” CDC image

Hannah Song, BA
Medical studen
Harvard Medical School and
Jennifer T. Huang, MD
Division of Immunology, Dermatology Program
Boston Children’s Hospital
Boston, MA

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Infection with the varicella-zoster virus leads to chickenpox, or primary varicella. The virus then lies dormant and can later reactivate as shingles, or herpes zoster.  Varicella-zoster vaccine is made of an attenuated live virus that prevents most people from getting chicken pox, but rarely can reactivate and cause shingles.

There were several pediatric patients who presented to our clinics with shingles/herpes zoster that was localized to one extremity. My hunch was that the extremity where the patients had shingles could be the same limb where they had received vaccination. We called the patient’s pediatricians because pediatricians typically document the extremity where the vaccination is given, and confirmed the theory that shingles in vaccinated children may be more likely to occur at the site of vaccination. Importantly, vaccination may modify the classic appearance of shingles, and you might see pink and red papules and pseudovesicles, rather than classic grouped fluid-filled vesicles on a red base.  Continue reading

Acne Sufferers At Increased Risk of Depression

MedicalResearch.com Interview with:
“Young man with acne” by Sergey Sudeykin (Russian, Smolensk 1882–1946 Nyack) via The Metropolitan Museum of Art is licensed under CC0 1.0Isabelle Vallerand, Ph.D.
Epidemiologist, MD Student
Dept. of Community Health Sciences
Cumming School of Medicine
University of Calgary

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Over the past few years, there have been numerous reports that an acne drug called isotretinoin (Accutane) has been linked to psychiatric disorders. We recently published a systematic review on this topic and did not find an increased risk of psychiatric disorders among people treated with isotretinoin, so we wondered if acne itself may be contributing to mental illness. While it is well known that acne can have negative effects on mood, we wanted to assess if there was an increased risk of true clinical depression using medical records data.

Therefore, we conducted the current study and found that acne increased the risk of developing clinical depression by 63% in the first year following an acne diagnosis and that this risk remained elevated for 5 years after the initial acne diagnosis.

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Potentially Cancerous Genital Lesions Common in Transplant Population

MedicalResearch.com Interview with:

Dr. Christina Lee Chung, MD Associate Professor Department of Dermatology Drexel University

Dr. Chung

Dr. Christina Lee Chung, MD
Associate Professor
Department of Dermatology
Drexel University

MedicalResearch.com:  What is the background for this study?  What are the main findings?

Response: In early 2016, five years after the inception of our specialty medical-surgical transplant dermatology center, we realized our nonwhite transplant patients were developing skin cancer at higher rates and found interesting trends. These data were published in a previous manuscript. One of the more striking findings was that these patients were developing a high proportion of skin cancer in non-sun-exposed areas such as the genital region. There are no standard guidelines regarding genital skin evaluation and it is unclear how often it is performed in any capacity amongst dermatologists, including practitioners in our center, quite frankly. Our group was concerned that we could be missing skin cancers in this “hidden” area in our high-risk organ transplant population so we launched a quality improvement initiative that incorporated thorough genital skin evaluation as a standard part of post-transplant skin cancer screening.   

Fifteen months after we started this modified screening process, we decided to evaluate the results. To account for any variation in examination, we looked at the findings of a single practitioner.

We found that genital lesions are common in the transplant population and include high rates of genital warts and skin cancer. However, patient awareness of the presence of genital lesions was alarmingly low. Nonwhite transplant patients, Black transplant recipients in particular, were disproportionately affected by both genital warts and genital skin cancer in our cohort. Similar to cervical cancer, high-risk HPV types were closely associated with genital squamous cell carcinoma development in our transplant population. Continue reading

Physicians Overwhelmed by Messaging From Electronic Medical Records

MedicalResearch.com Interview with:
“Computer” by FullCodePress is licensed under CC BY 2.0Matilda W. Nicholas,
 MD, PhD
Duke Dermatology
Durham, North Carolina

MedicalResearch.com: What is the background for this study?

Response: I have found many physicians overwhelmed by the electronic messaging feature in Electronic Health Record systems (EHRs). I found there was very little published about this phenomenon, particularly for specialists. So, we set out to take a look at the volume and effect these systems have. 

MedicalResearch.com: What are the main findings?

 Response: We found that, on average, clinicians receive 3.24 messages per patient visit, for an average of about 50 messages per full day of clinic. The number of messages also correlated with poor reported work life balance for dermatologists. Continue reading

Atopic Dermatitis: Skin Microbiome Altered in Lesional and Non-Lesional Skin

MedicalResearch.com Interview with:

“Eczema” by NIAID is licensed under CC BY 2.0

Eczema – Atopic Dermatitis

Maja-Lisa Clausen MD, Ph.D.-fellow
Department of Dermatology
Copenhagen University Hospital Bispebjerg 

MedicalResearch.com: What is the background for this study?

Response: ​The human microbiome seems to play an important role in health and disease, by influencing host cells and contributing to host immunity. A balanced interplay between host cells and resident bacteria is important, and dysbiosis is linked to several diseases, including skin diseases like atopic dermatitis. Patients with atopic dermatitis suffer from ​frequent skin infections, and their skin microbiome is dominated by S. aureus. Frequent skin infections lead to frequent use of antibiotics, and with worldwide increase in resistant bacteria, a better understanding of the interplay between host and bacteria is paramount in order to develop new treatment strategies.

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Patronizing Hair and Nail Salons Linked To Increased Risk of Skin and Fungal Infections

MedicalResearch.com Interview with:
Lindsey Milich Rutgers School of Public Health studiesLindsey Milich

Rutgers School of Public Health studies
 

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Much of the spotlight has been focused on hair and nail technicians, with the focus now shifting towards the health and safety of hair and nail salon clients. We wanted to assess perceived safety and health risks and prevalence of respiratory and dermal symptoms among hair and nail salon clients in New Jersey.

Main findings include dermal/fungal symptoms being more prevalent among clients who visited salons three or more times within the past year, compared with those with fewer reported visits. Respiratory symptom prevalence was higher among clients with fewer salon visits, indicating a “healthy client effect”; clients with these symptoms may be less likely to return.

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Atopic Dermatitis: IF Used At All, Systemic Steroids Should Be Short Term Bridge To Other Therapies

MedicalResearch.com Interview with:

Dr. Jonathan L. Silverberg MD PhD MPH Assistant Professor in Dermatology Medical Social Sciences and Preventive Medicine Northwestern University, Chicago, Illinois

Dr. Jonathan Silverberg

Dr. Jonathan L. Silverberg MD PhD MPH
Assistant Professor in Dermatology
Medical Social Sciences and Preventive Medicine
Northwestern University, Chicago, Illinois

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Systemic corticosteroids are commonly used as systemic treatments for atopic dermatitis. However, few studies assessed the efficacy and safety of systemic corticosteroids in atopic dermatitis. This systematic review sought to summarize the available evidence for their use in atopic dermatitis.

Overall, 52 reviews and 12 studies were included in this systematic review. Most studies suffered from small sample size, low quality. In one of the only randomized-controlled trials performed, systemic corticosteroids were less effective than cyclosporine and led to more rebound flares. There were numerous safety and tolerability concerns with both short and long-term treatment with systemic corticosteroids. One study found that even short-term use of systemic corticosteroids was associated with increased sepsis, venous thromboembolism and fractures.

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Current Sunscreens Lack Protection Against Damaging Effects of Visible Light

MedicalResearch.com Interview with:
Prof. Dr. Mauricio S. Baptista
Chemistry Institute (IQ-USP)
University of São Paulo
Brazil 

“Tanning in the sun” by S B is licensed under CC BY 2.0MedicalResearch.com: What is the background for this study? What are the main findings?

Response: This research started around 7 years ago. Our lab had a lot of previous experience in studying how photosensitizers (molecules that absorb light and transfer energy to others in its surroundings) used for Photodynamic Therapy, behave in the intracellular environments. We realized that most scientific work that defined the effects of sun in skin did not really consider looking into the properties of the molecules that are naturally found in skin and that absorb light. We also realized that very likely natural photosensitizers present in the skin behaves similarly when excited by either UVA or visible light. It all depends on which molecule absorb light and how the subsequent excited states behave. The work started by looking at melanin and melanocyte cells (Chiarelli-Neto et al Free Radic Biol Med 2011, 51, 1195; Chiarelli-Neto O et al. PLoS ONE, 2014  9(11): e113266). More recently we start looking at keratinocytes  and liposfucin (Tonolli et al Journal of Investigative Dermatology 2017, 137, 2447).

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Natural Selection For Skin Color Varies With Latitude

MedicalReseaerch.com Interview with:

These are South African individuals in a household that exemplify the substantial skin pigmentation variability in the Khomani and Nama populations. Picture taken with consent for publication.

These are South African individuals in a household that exemplify the substantial skin pigmentation variability in the Khomani and Nama populations. Picture taken with consent for publication.
Image by Brenna Henn

Alicia R. Martin PhD, Postdoc
Department of Genetics
Stanford University
Department of Medicine, Massachusetts General Hospital and Harvard Medical School
Stanley Center for Psychiatric Research, Broad Institute, Cambridge, MA and

Brenna M. Henn, Phd, Assistant Professor
Department of Ecology and Evolution
SUNY Stony Brook, NY 

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Skin pigmentation varies more in Africa than in any other continent, and yet genetic studies of this and other traits are massively underrepresented there. Previous Eurasian study biases have instead focused on populations that vary less and have fewer variants contributing to baseline skin color.

In our study, we compiled quantitative skin color measurements from a large, globally diverse set of individuals and populations to show that pigmentation varies more closer to the equator than in high latitude populations. We focused on the ‡Khomani San and Nama populations from South Africa, which diverged early along the modern human lineage from other populations and have lighter skin than equatorial Africans. We showed that skin pigmentation is roughly 100% heritable, but that previously identified genes make up a tiny fraction (~10%) of the variation present in these populations. We identified both known and new genes contributing to this variability.

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